Why is my stool black?
I know that stool, as a metabolic waste product of the body, is often most overlooked by people. Even changes in its shape and color can indicate a problem. So, what does it mean when you pass black-colored stool?
Doctor's answer (1)
Black stool can have several possible causes, some of the common ones include:
1. Dietary factors: Consuming animal blood products such as pig's blood or duck's blood, or eating large amounts of foods rich in melanin like black sesame seeds or black fungus may cause iron or melanin in the food to combine with sulfides in the intestine, forming black iron sulfide and resulting in dark-colored stool. This condition is usually normal and generally not a cause for concern.
2. Medication factors: Certain medications, such as iron supplements or bismuth-containing drugs, may also cause black stools. This occurs when these medications combine with sulfides in the intestine, forming dark-colored substances. The stool color typically returns to normal after discontinuation of the medication.
3. Gastrointestinal bleeding: Bleeding in the gastrointestinal tract may occur in the upper digestive tract, including the esophagus, stomach, and duodenum. As blood passes through the digestive system, the iron in hemoglobin may be oxidized due to the effects of gastric acid and digestive enzymes, forming iron sulfide, which causes the stool to appear black, sticky, and tar-like.
If black stool persists, medical attention should be sought promptly.
